Opioids are psychoactive molecules that resemble morphine or similar molecules in their pharmacological effects. The primary therapeutic use of opioids is to produce an analgesic effect, otherwise referred to as a painkiller effect, whereby the perception of pain is decreased and the tolerance of pain is increased. Opioids are amongst the world's oldest known drugs, with examples of the morphine molecule being extracted from poppy flowers found in recorded history. Morphine, one of the most commonly known opioids, has the chemical formula C17H19NO3 and its molecular structure is well known.
Opioids operate on humans by binding to opioid receptors, which are primarily located in the central and peripheral nervous system and the gastrointestinal tract. Today, the primary clinical use of opioids is the treatment of severe pain such as post-operative pain. Although opioids are amongst the best known drugs for effective relief of severe pain, there are many undesirable side effects of opioids, which side effects include sedation, respiratory depression, constipation, nausea and vomiting, and addiction to the sense of euphoria it may induce. That is, ongoing administration of opioids may result in opioid dependence, leading to withdrawal symptoms upon abrupt discontinuation of opioids. Opioid dependence may also result in the need to increase the drug dosage over time to provide the same level of pain relief to the patient, which in turn may increase the unwanted side effects of the opioid.
A need has arisen for an opioid molecule that delivers effective pain reduction while decreasing or eliminating the undesirable side effects.